Two-speed supercharger



v March s, 1938. D. G. MaccuLLocH 2,110,711

TWO-SPEED SUPERCHARGER Filed Oct. 19, 1955 24 J4 $2 J2 46 T L x /16 O Zw 9) W INVENTOR.

w With reference to the drawing,

Patented Mar. 8, 1938 PATENT OFFICE 7 2,110,711 I 'rwo-srsnnsUrsacnAnGEa Donald G. Macculloch, Hawthorne, N. 3., assignor to WrightAeronautical Corporation, a corporation of New York Application October19, 1935, SerialNo. 453m "6Claims.

This invention relates to two-speed gearing, and in the specific showingof the drawing to a 1 two-speed drive suited for engine superchargers.

In .certain respects the invention comprises improvements on theco-pending application of Chilton, Serial No. 680,495, filed July 14,1933, and utilizes much of the structure there disclosed.

Objects of the invention are to simplify the construction by utilizingback gears for the redisclosed in the above 'identii'ied application.

Other objects of the invention will be obvious from or will be pointedout in the following description:

which is a longitudinal section through the shaft axes of the device, l8and I2 designate housings similar to those already in use forsupercharger drives, and

- l8 designates a conventional crankshaft exten-.

0 sion having a usual main driving gear l8 ,and

supported on a rear bearing l8, the usual crankshaft connection for thisshaft f8 occurring be- 'yond the left end of the figure. Freely mountedfor rotation around the extension shaft I8 is a 4 usual hollowsupercharger shaft, the right-hand end of which is indicated at 28 andwhich is equipped with a usual supercharger drive pinion I 22. Meshedwith this pinion 22 is a gear 28 splined to a layshaft 28, at 28, forunitary rota tion. This gear is-counterbored as a cylinder and containsan'hydraulic piston '88, the gear having splined into it, clutch plates82, 88, the latter being secured against axial motion by a locking ring88 engaging grooves in the splines.

Intermediate these plates are inner clutch plates .88 splined to anextension 88 of a pinion 82 which is at all times meshed with the maindriving gear l8 andis free for rotation on a bushing on the layshaft 28.This layshaft is supported in 40 end bearings 88, 88 in the housings l2and I8, respectively, and is provided with a cam hub 88 engagingrollers" 82 which are in turn engaged within a cylindrical projection 88of a low speed The layshaft 28 is hollow and is provided with a tubularmember 88 communicating at 18 with the clutch piston 88 and with acontrol valve indiduced speed drive in place of the planetary gears,cated in general at 12. This valve serves to' establish and cut offcommunication between an engine oil pressure lead (not shown) and thehigh speed clutch piston 88.

The operation of the device is as follows: The pinion '82 with thedriving high speed clutch plates 88 is at all times driven by the maingear l8 and in turn at all times drives the gear 88 of the shaft 88whose gear 82 at all times drives the gear 88 and roller clutch cylinder88 and, whenever the hydraulic clutch 88 is disengaged, the rollerclutch drives the layshaft and therefore the gear 28 at unitary speedwith the low speed gear 88.

It will be noticed that the gear train 82, 88, 82 88 results in thelatter gear and the clutch member 58 rotating at less speed than thepinion 82 and thereby low gear is effective whenever the valve 12 isoperated to cut of! oil pressureto the running in the usual way topermit of this high speed'drive. Whenever the valve 12 is closed,

releasing the hydraulic clutch 88, the drive .will' automatically "fallback to be picked up by the roller clutch at the instant the speed fallsto the lower speed of this roller clutch driving member.

By adding the gear 82-to the otherwise conventional accessory driveshaft 88 and providing the gear 88 in place of the planetary gears ofthe Chilton application, a simplified structure is provided, the generalobjects. and advantages of 'which are similar to those set forth in thatapplication. It will be seen that the shaft 88 with its gears 88 and 82comprises a-fback, gear" organization consisting of theback gear shaft88 and back gears 88 and 82 somewhat similar to "that used on a lathe.Operation of the device as a speed'reduclng'drive is simplified by theuse of the overrunning clutch 88, 82, 88 and by the use of the simplehydraulically operated clutch in the gear 28. when the oil pressure tothe piston 88 is turned off by the valve [2,- normal leakage of oilbetween the several relatively rotating parts will pe t the pressurebehind the piston to drop off qufiy to permit clutch release, where-.upon the drive falls back on the back gears While I have described myinvention in detail in its present preferred embodiment, it will beobvious to those skilled in the art, after understandin the appendedclaims tocover all such modifications and changes.

What is claimed is:

1. The combination with an engine having a supercharger drive gear and asupercharger pinion, of a layshaft including a gear meshed with saidsupercharger pinion, a pinion meshed with said supercharger gear androtatable on the layshaft, a second gear on said layshaft, a back-gearshaft, and gears on said back-gear shaft drivably connecting the secondsaid layshaft gear and the layshaft pinion.

2. An engine superchargerdrive comprising in combination, a drivinggear, a supercharger pinion, a layshaft, a gear and a pinion on thelayshart respectively engaged with the first said.

pinion and gear, one driving connection between said layshaft pinion andsaid layshaft gear comprising a back gear shaft having a'gear engagedwith said layshaft pinion and gears drivably connecting said back gearshaft and said layshaft gear, and another driving connection comprisingclutch means for selectively connecting said layshaft gear directly tothe layshaft pinion.

3. The combination with an engine of a supercharger drive gear, asupercharger pinion, a layshaft having ,a pinion and a gear,-respectively, engaged with said supercharger gear and supercharger pinion,selectively operable means for clutching said layshaft pinion and geartogether for unitary rotation, and. a back gear set operative upondeclutching of said layshaft gear from said layshaft pinion for drivingsaid layshaft gear at a lesser speed than the speed of said pinion, saidback gear set having driving relationship with said layshaft pinion andincluding a one-way clutch driving connection with said layshaf t gear.

4. The combination in an engine supercharger drive, of a superchargerpinion, a layshaft having a gear meshed with the pinion, a driven pinionloosely' mounted on the layshaft, clutch means selectively operable todrivably connect said layshaft gear directly with said layshaft pinion,and back gears providing a driving connec- 5. The combination with anengine having a i drive gear anda supercharger pinion, of a layshafthaving a pinion and gear respectively meshed with said drive gear andsaid supercharger pinion, a back gear shaft having a back gear drivablyconnected with said drive gear, gears establishing a driving connectionbetween said back gear and said layshaft gear, a first clutch meansorganized to selectively directly connect and disconnect the layshaftpinion to and from the layshaft gear, and a second clutch meanscomprising a part of one of the gears which establish the drivingconnection between the back gear and the layshaft gear for drivablyconnecting said back gear with said layshaft gear upon disengagement ofsaid first selective clutch means.

6. The combination with an engine having a drive gear and a superchargerpinion, of a layshaft having a gear rotatable therewith and having apinion loosely mounted thereon, said gear and pinion being respectivelyengaged with said supercharger pinion and with said drive gear, a

slow speed gear on said layshait, means for driving said slow speed gearfrom said drive gear, a one-way overrunning clutch between said slowspeed gear and the layshaft arranged for overrun of the slow speed gearby the layshait, and a clutch selectively operable to connect said layshaft with the layshaft pinion for unitary rotation at a speed greaterthan that of said slow speed gear, said layshaft, when said selectiveclutch is disconnected, dropping back forrotation with the slow speedgear through said one-way overrunning clutch.

DONALD G. MACCULLOCH.

